Furnace conveyer and method of treatment



J 3, 1939- o. R. OLSON ET AL. 2,142,824

FURNACE CONVEYER AND METHOD OF TREATMENT Filed Oct. 12, 1937 Arch V. Riffs Patented Jan. 3, 1939 UNITED STATES PATENT OFFIQE FURNACE CONVEYER AND NLETHOD OF TREATMENT ration of Pennsylvania Application October 12, 1937, Serial No. 168,558

2 Claims. (Cl. 263-6) This invention relates broadly to furnaces, and particularly to furnaces having conveyers therein, whereby material may be transported therethrough for metallurgical treatment. The invention has special reference to furnaces of the continuous or tunnel type for the normalizing of sheet steel, although other applications will doubtless occur to those skilled in the art.

In the manufacture of sheet steel, it is almost universal practice to subject the material to normalizing to improve its physical characteristics. Ordinarily this operation is conducted by passing the material, either in the form of single sheets or packs, through an elongated furnace chamber by conveyer means extending therethrough. It has been found that accretions of oxide tend to build up on the supporting surfaces of such conveyer means in the form of sharp points. Such accretions seriously mar the surface finish of the material being treated, and to avoid this, it has become the practice to employ so-calied waster sheets under the prime material being treated. Various other expedients have been proposed and. tried out to prevent injury to the material during its passage through the furnace, but none of them, so far as we are aware, is without serious objections. The use of waster sheets referred to above, for example, increases the amount of material to be handled at both the entrance and delivery ends of the furnace, and it is also necessary to return the waster sheets from the latter to the former.

We have invented a furnace conveyer and a method of treatment applicable to existing furnace conveyers, whereby the aforementioned difficulty is entirely eliminated.

In accordance with our invention, we apply to the supporting surface of a furnace conveyer, a layer of refractory or ceramic material capable of forming a firm bond with such surface and having a fusion or melting point higher than the normal operating temperature of the furnace. A complete understanding of the invention may be obtained from the following detailed description thereof, referring to the accompanying drawing illustrating several embodiments of the furnace and the preferred practice of the method of our invention. In the drawing:

Figure l is a diagrammatic side elevation of a furnace of the type to which our invention is particularly applicable;

Figure 2 is a partial sectional view taken transversely of the furnace;

Figure 3 is a partial side elevation of a conveyer element adapted to be installed in the furnace;

Figure 4 is a view similar to Figure 2, showing I a modified form of furnace coneveyer;

Figure 5 is a partial elevation of one of the elements of the conveyer illustrated diagrammatically in Figure l;

Figure 6 is a view similar to Figure 2, showing refractory brick assembled within a framework composed of structural members I I. The furnace chamber is adapted to receive material at one end and discharge it from the other end, traveling therethrough on suitable conveying means indicated diagrammatically in Figure 1 at I2. Doors I3 and I4 are provided for closing the entrance and delivery ends of the furnace to the desired extent. The furnace may be heated by any convenient means, not shown.

Figures 2 and 3 indicate one type of conveyer element installed in the furnace I0 and the application thereto of our invention. As shown in these figures, a conveyer is composed of a plurality of blades I5 having supporting rollers I 6 traversing a track I! suitably supported below the furnace hearth. The blades, themselves, project upwardly through the slot I8 in the hearth. Although only one slot and one conveyer chain are indicated in Figure 2, it will be understood that two or more such chains are provided and that suitable guiding and driving sprockets are disposed at each end of the furnace. The blades I5 are linked together in chains by links IS.

The blades I5 have supporting surfaces 20, on which steelsheets, for example, may be placed either singly or in packs. We apply to these surfaces a layer 2| of refractory material such as ceramic paint. This is a standard article of commerce and is obtainable in the open market. The material is sufliciently fluid, when cold, to permit of its being brushed or spread on the supporting surfaces and it has the property of forming a progressive bond with the blades I5, which are usually of high temperature alloy steel, on repeated heating. After the ceramic paint has been applied to the surfaces 20, it is burned on by operating the conveyer chains through the furnace while the latter isheated to normal operating temperature. The layer 2| thus forms a tight bond with the surfaces 20, and after the burning operation, the refractory material of which the layer 2| is composed, loses its initial fluidity and remains solid at the temperature at which the furnace is normally operated, viz., 1700 F.

The layers 2| on the surfaces 20 prevent the the aforementioned advantages, the treatment contemplated by our invention is relatively inexpensive and can be applied to a furnace of almost any type in a relatively shortY ti e, whether newly constructed or previously. jus'e The nature of the refractory layers 2|, furth more, is such that they do not wear out quic ly and thus do not require frequent renewal.

Figure 4 illustrates .a furnace conveyer of, e walking beam type having a plurality of groups of bars 22 and 23, alternately raised and lowere'd and moved longitudinally of the furnace tomove' 1 therethrough material disposed on the bars. :As shown in Figure 5, our invention may be applied a to the bars in the groups 22 and 23 by applying a layer of ceramic paint 24 to the supporting.

surfaces thereof. I

Figures 6 and 7 illustrate the application oi the invention to a furnace conveyer of the roller,

bond it to them.

mounted shafts 25 extend transversely through the furnace and are provided with supporting disks 26, spaced longitudinally of the shafts. The shafts are spaced along the length of the furnace close enough together so that sheet material is passed from the disks of one shaft to those of the next. We apply to the peripheries of the disks 26 a layer of ceramic paint 21, as shown in Figure 7, in the manner already described. The result of this treatment is the same as that of those described above, that is, the prevention of the accumulation of oxide deposits on the sheetsupporting surfaces of the conveyer.

Although we have illustrated and described only a preferred practice of the method of our invention and a few forms of apparatus to which it is applicable, it will be understood that changes I while traversing a furnace, comprising a movable supporting member, and means preventing the building up of oxide accretions on the article engaging surface of said member including a ceramic coating bonded to said surface.

2. A method of treating the work supporting surfaces of a furnace conveyer to prevent accumulation of oxide accretions from the material carried on such surfaces, including the steps of coating said surfaces with a ceramic material and firing said surfaces to fuse said coating and OSCAR R. OLSON. ARCH V. RITTS.

hearth type. In this type of conveyer, rotatablyi I 

